1. Field of the Invention
The present invention relates to rotary electric, machines for a vehicle, and particularly relates to a rotary electric machine for a vehicle, having a structure for cooling a coil of a stator.
2. Description of the Related Art
For conventional rotary electric machines for a vehicle, in order to reduce temperature increase when a coil of a stator is energized, methods of directly discharging cooling oil to coil portion have been proposed. Among them, many implementations have been reported in which a hollow shaft or the like is used to splash cooling oil from the inside of a rotor toward coil end portions configured on both sides in the axis direction of a stator, thereby achieving cooling.
[Patent Document 1] JP-A-2010-57261
However, for a flat multipole motor in which concentrated winding is employed as a winding specification of the stator, indeed cooling oil splashed from the inside of the rotor onto the coil end portions can reduce temperature increase of the coil end portions, but the cooling oil is not directly splashed onto a middle portion in the axis direction between phases of the coil, providing less cooling effect to the middle portion than that to the coil end portions, causing the coil temperature to tend to increase. This may increase local heat deterioration of the coil.
In order to solve the problem, the Patent Document 1 has proposed a method of providing a nozzle on the upper portion of the coil ends to directly cool between phases of the coil ends. This method enables cooling between phases of a coil that is difficult to be cooled. However, this method requires configuration of parts in which many holes are provided on the upper portion of the stator, which raises a problem of increasing the number of parts and increasing the number of machining processes for providing passages.